Here’s the TL;DR version. Pasting text copied from any text app into an FCP X title will change the title font to that of the pasted text. Really cool. Text pasted into the Inspector won’t change the selected style.
EDIT: Works with text copied from a web browser too, So it’s a Mac OS thing, it works when you paste styled text into any text app.
I got this from Brian Elliot Tate, who noticed that if you copy and paste text from a font browser into an X title it will change the font. Here’s a link to the video he made showing this.
So… I poked around a bit and discovered that this works with text copied from anything. Text Edit, Pages, Word, even PDF’s. Any styled text. If you have the font, it’ll work. Try it!
Final Cut Pro X Babbling 
I shall stand and deliver – thanx Charlie
Funny, I always thought that was the part everyone knew, and not the other way around. Most I know don’t even realize there is a text box in the inspector or think to enter text there instead of in the viewer. 😄
LOL. Sometimes the simple things are the least obvious. To me. 😉
Ironically, I only knew this because it drove me NUTS that the text formatting would come along for the ride, but fortunately knew from Motion how to do it, where it’s the same scenario. Annoying (for me), but certainly a nice option to have if needed.
Now if only they’d make it that you can select a font by TYPING THE FIRST LETTER(S)… !